Trimming an article can be a tedious and boring process, especially when a high number of repetitive cuts need to be made, even with the use of a powered cutter, the constant re-positioning of the powered cutter can lead to operator hand and wrist fatigue in having issues similar to the well-known carpal-tunnel syndrome from a high number of repetitive hand and wrist motions. Another issue can be the oil or tar resin present in the article that can gum up the cutting blades of the cutting apparatus, requiring frequent blade cleaning. Most cutting apparatus are designed for general use in that they can be applied to a number of different cutting uses, from fabric, to sheet steel, to wire mesh, to plant and tree pruning, to paper, to hair, to cardboard, to wood sheeting, and so on. Each one of these cutting apparatus uses ideally has specialized cutting blades, i.e. sharpness, clearance, blade cutting pattern, material of the cutting blade, speed of the cutting blades coming together, the force of the blades coming together, the angle that the blades come together, how tightly clamped the blades are to one another at their mutual pivot point, and so on.
However, there are additional issues with the cutting apparatus outside of the cutting blade specifics described above that concern user or operator fatigue, as most cutting apparatus tasks are limited in the amount of time or the amount of cutting that is done, i.e. cutting fabric for a single sewing project, this issue of operator fatigue is typically not addressed. This is mostly due to the fact that when a large amount of cutting is required, such as the mass production of clothing in manufacturing thus requiring many thousands of clothing items with the required fabric cutting being done on a large scale would be partially or totally automated, not only to save time, but to ensure constant repetitive quality in the fabric cutting. Thus, when the cutting situation arises wherein one would have the need to do fairly high volumes of repetitive cutting, however, not enough cutting volume to justify automation, the problem arises of operator fatigue is using for instance a handheld cutting apparatus and doing a high number of repetitive cutting motions.
This leads to the need for design modifications to reduce operator fatigue in using the handheld cutting apparatus for highly repetitive cutting motions, these design modifications would include ways to minimize fixed hand and wrist positioning, i.e. facilitating a variety of different hand and wrist motions for accomplishing the same cutting function. Further, structure to make separable blade cleaning easy, as this is mostly an issue with the article to be trimmed is of an organic nature and can leave a residue on the cutting blade during use that can act to impair the cutting blades efficiency and increase friction as between the blades, thus overloading the drive motor.
In looking at the prior art in U.S. Pat. No. 3,631,596 to Glaus, disclosed is an electric scissors assembly having a stationary blade and an independently oscillating blade driven by a motor, all mechanical and electrical parts, particularly the scissors, motor and battery being accommodated and mounted in a handle-shaped casing made of two assembled parts of plastic material without any screw-fastened portions by means of elastic portions latched to the casing, and all of the mechanical and electrical parts being readily exchangeable. Glaus has a Teflon slider ring 10 that is inserted between the cutting blades to reduce friction thus reducing motor power required therethrough the eccentric motor drive 23, requiring minimal space, see FIGS. 2 and 3. In Glaus, the focus is upon the mechanism of the scissors having ease of assembly and disassembly, wherein the scissors cutting head and the motor/drive mechanism are a single assembly, as best shown in FIGS. 1 and 3. Glaus has no teaching relative to an axially pivoting scissors head that is independently removable.
Continuing in the prior art in U.S. patent application Ser. No. 2013/0247384 to Ishiguro, disclosed is an electric scissor that is provided with; a moving first blade, a moving second blade, a toggle link mechanism including a first link, a second link, and a drive shaft; and a drive section. In Ishiguro, one end of the first link is rotatably connected to a transmission portion of the first blade and one end of the second link is rotatably connected to a transmission portion of the second blade. Ishiguro has the other end of the first link rotatably connected to the other end of the second link through the drive shaft. The drive section in Ishiguro is configured to open/close the first blade and the second blade by displacing the drive shaft in a direction perpendicular to an axial direction of the drive shaft. The toggle link mechanism in Ishiguro has the advantage of increasing the mechanical advantage of the cutting blade to cutting blade closing force as the cutting blades are drawn closer together, thus according to Ishiguro added cutting force between the blades in created when it is needed most, being near the end of the cut, i.e. specifically for tree branch pruning. The drawback of the Ishiguro toggle link mechanism is in its size, requiring a significant amount movement space as shown in FIGS. 1, 2, 4, and 5. The increasing mechanical advantage of the toggle link can best be seen in going from FIG. 1 to FIG. 2, and the graph in FIG. 3. Ishiguro also has no teaching relative to an axially pivoting scissors head that is independently removable.
Further, in the prior art in U.S. Pat. No. 3,693,254 to Salonen disclosed is a portable, hand-held shearing implement, which includes a pair of cutting blades employing a motor powered mechanism to apply the cutting force, Salonen having a similar toggle link blade cutting mechanism to Ishiguro thus providing for increased mechanical advantage in proportion to the closing of the blades together. The invention in Salonen is particularly adaptable for an implement to execute individual, deliberate, cutting strokes, i.e. such that a single “cut” can be selectably executing such that the cutting blades are just moved together a single time as desired, this is as opposed to most powered cutting blades that of necessity continuously move together and apart from one another, wherein a single selectable blade cut cannot be executed.
One version in Salonen may be powered by an electric motor or a self-contained internal combustion engine, driving through a gear reduction train to a reciprocatory mechanism having threaded means with a releasable coupling to drive the power stroke. Another version in Salonen employs a controllable reversing switch to effect the reciprocative action and is limited to an electric motor drive. In the former version of Salonen, reopening of the blades is spring actuated with provision included to soften the impact of termination, and includes a triggering means to stop and hold the reciprocative action after each cycle until released by trigger actuation. Also Salonen also has no teaching relative to an axially pivoting scissors head that is independently removable.
Moving onward in the prior art in U.S. patent application Ser. No. 2013/0000130 to Maniwa disclosed are electric scissors, a rotating motion of a motor is converted into a linear motion, and a link mechanism is operated to open and close blades by the linear motion, again wherein the closing force is increased when the blades are moved toward one another, similar to Ishiguro and Salonen. The electric scissors in Maniwa include a current control unit that controls an electric current value to the motor, and a detection unit that detects that an angle between the blades becomes a predetermined angle.
The current control unit in Maniwa changes an upper limit of the electric current value to be supplied to the motor when the detection unit detects that the angle between the blades becomes the predetermined angle, thus resulting in blade closing force control via motor current control and not having to have excessively strong linkage and blade components that would be required otherwise similar to the linkage action of bolt cutters that must withstand very high near blade closing cutting forces. Further, Maniwa also has no teaching relative to an axially pivoting scissors head that is independently removable.
Continuing, in the prior art in U.S. Pat. No. 3,787,742 to Murphy disclosed is an electric shear assembly in which there is provided a housing having swingably interconnected first and second cutting blades mounted therein and projecting outwardly therefrom. In Murphy, a gear train is mounted within the housing and is interconnected between a reversible electric motor and a second blade for moving the second blade with respect to said first blade, i.e. such that only the second blade is moving. Also in Murphy a manually manipulatable switch assembly is mounted on the housing and is coupled through a second switch assembly for actuating the motor to drive the gear train in a first direction to cause the cutting blades to open and close.
Further in Murphy a cam driven by the gear train is engagable with the second switch assembly for selectively opening and closing the assembly to control the motor to drive the gear train in a second direction for an interval sufficient to position the cutting blades in an open position and deactuate said motor. In Murphy a cam type arrangement is used to transmit motor rotational action to closing pivotal movement of the blade, requiring a motor to be reversible to go from blade closing movement to blade opening movement, wherein the blade closing movement for instance can be selectively stopped at any point to help prevent a finger injury from the closing blade, and by having a slow moving cutting stroke. Also, Murphy also has no teaching relative to an axially pivoting scissors head that is independently removable.
What is needed is a cutting apparatus that can accommodate on a functional output basis a high number of similar cutting tasks, however, without imparting excessive fatigue upon the operator of the cutting apparatus. Thus would be accomplished by de-coupling or buffering the functional end task of the cutting blades from the hand and wrist movement required of the cutting apparatus operator through variable structure to alter positional orientations as between the cutting blades and the operator's hand and wrist. Further desired would be structure to allow easy cleaning of the cutting blades to be able to keep them at their optimum cutting efficiency.